ABSTRACT
[This corrects the article DOI: 10.1021/acsomega.3c09667.].
ABSTRACT
Diterpenoid tanshinones (DTs) are a bioactive fraction extracted from Salvia miltiorrhiza. High-performance liquid chromatography analysis revealed the presence of four compounds, namely, tanshinone IIA, tanshinone I, cryptotanshinone, and dihydrotanshinone. In this study, we aimed to propose a possible mechanism for the anti-lung cancer effect of DT. To do so, we utilized a lung cancer nude mice model and a lung cancer cell line (PC9) to investigate the effect of DT on lung cancer. We employed immunohistochemistry, enzyme-linked immunosorbent assay, hematoxylin and eosin staining, and immunofluorescence to analyze the pharmacological role of DT in the inhibition of lung cancer growth. The results showed that DT inhibited tumor growth, induced apoptosis in the nude mice model, and reduced inflammatory cell infiltration. Additionally, DT inhibited PC9 lung cancer cells, growth, proliferation, and migration. The mechanism of action of DT involves not only directly inhibiting cell proliferation and migration but also improving the tumor microenvironment. DT significantly increased the expression of important intestinal gap junction proteins, such as zonula occludens 1 (ZO-1) and occludin I. This upregulation contributes to the reinforcement of the intestinal mucosal barrier, thereby reducing the paracellular transport of lipopolysaccharides (LPS) through the intestine. Consequently, the decreased LPS levels lead to the inhibition of NF-κB expression and downregulation of macrophage polarization, as indicated by the decreased expression of CD68. In conclusion, this study has confirmed that DT has anti-lung cancer properties by improving the inflammatory tumor microenvironment via regulating macrophage polarization and inhibiting LPS-associated immune response. These results provide new insights into the mechanism of DT action against lung cancer.
ABSTRACT
Objective: To evaluate the effectiveness and safety of a combined treatment for moderate and severe androgenetic alopecia (AGA) involving the use of electric microneedles. Methods: A total of 83 patients with moderate to severe AGA in the Department of Dermatology at Beijing Jishuitan Hospital were included in this study. The male patients were administered finasteride orally and 5% minoxidil for external use, while the female patients were given spironolactone orally or Diane-35 and 2% minoxidil for external use. All the patients were then treated via electric microneedle therapy alongside the YUFA ®medical care package (Foshan, China) once a week for 1-28 weeks. The seven-point method and root hair measurement using a hair mirror were adopted to evaluate the efficacy and any adverse reactions of the combined treatment. Results: Eleven patients were treated for 1-3 weeks, 60 for 4-12 weeks, and 12 for more than 12 weeks. The efficacy evaluation using the seven-point method for 12 weeks of treatment indicated a 100% response rate, specifically, a 42.1% mild improvement rate, a 38.6% moderate improvement rate, and a 19.3% marked improvement rate. Besides, the efficacy assessment was also completed with root hair count method and the number of hair roots measured at fixed points were 148.67±11.15, 158.13±5.11 and 169.75±2.06 after treatment time at 16, 20 and 24 weeks, respectively. Of note, a statistical difference in the number of hair roots could be observed during the period of week 20-week 24 (P < 0.01). Conclusion: The combined treatment of moderate to severe AGA using the electric microneedle technique has a clear effect and can effectively increase the hair density. With a simple operation and mild side effects, the technique has wide application prospects.
ABSTRACT
Cardiac hypertrophy is a common pathological process of various cardiovascular diseases and eventually develops into heart failure. This paper was aimed to study the different pathological characteristics exhibited by different mouse strains after hypertrophy stimulation. Two mouse strains, A/J and FVB/nJ, were treated with isoproterenol (ISO) by osmotic pump to induce cardiac hypertrophy. Echocardiography was performed to monitor heart morphology and function. Mitochondria were isolated from hearts in each group, and oxidative phosphorylation function was assayed in vitro. The results showed that both strains showed a compensatory enhancement of heart contractile function after 1-week ISO treatment. The A/J mice, but not the FVB/nJ mice, developed significant cardiac hypertrophy after 3-week ISO treatment as evidenced by increases in left ventricular posterior wall thickness, heart weight/body weight ratio, cross sectional area of cardiomyocytes and cardiac hypertrophic markers. Interestingly, the heart from A/J mice contained higher mitochondrial DNA copy number compared with that from FVB/nJ mice. Functionally, the mitochondria from A/J mice displayed faster O2 consumption at state III with either complex I substrates or complex II substrate, compared with those from FVB/nJ mice. ISO treatment did not affect mitochondrial respiratory control rate (RCR), but significantly suppressed the ADP/O ratio generated from the complex II substrate in both strains. The ADP/O ratio generated from the complex I substrates in A/J mice declined by 50% after ISO treatment, whereas FVB/nJ mice were not affected. These results suggest that, compared with FVB/nJ mice, A/J mice possesses a poor integrity of mitochondrial respiratory chain that might contribute to its vulnerability to ISO-induced cardiac hypertrophy.
Subject(s)
Cardiomegaly , Heart Failure , Animals , Cardiomegaly/chemically induced , Isoproterenol/metabolism , Isoproterenol/toxicity , Mice , Mitochondria , Myocytes, Cardiac/metabolismABSTRACT
Melanocytes, derived from neural crest cells, are involved in melanin production. This protocol describes a method to generate induced melanocytes (iMelanocytes) from human induced pluripotent stem cells (iPSCs) using a suspension culture system, which considerably improves the differentiation efficiency. The most critical parts of this protocol are the selection of a reliable iPSC line with strong potential to differentiate into melanocytes and their stemness maintenance. For complete information on the use and generation of this protocol, please refer to our Cell Reports article, Liu el al. (2019).
Subject(s)
Cell Culture Techniques/methods , Induced Pluripotent Stem Cells/cytology , Melanocytes/cytology , Cell Differentiation/physiology , Cells, Cultured , Humans , Neural Crest/cytologyABSTRACT
Human induced pluripotent stem cells (hiPSCs) are invaluable resources for producing high-quality differentiated cells in unlimited quantities for both basic research and clinical use. They are particularly useful for studying human disease mechanisms in vitro by making it possible to circumvent the ethical issues of human embryonic stem cell research. However, significant limitations exist when using conventional flat culturing methods especially concerning cell expansion, differentiation efficiency, stability maintenance and multicellular 3D structure establishment, differentiation prediction. Embryoid bodies (EBs), the multicellular aggregates spontaneously generated from iPSCs in the suspension system, might help to address these issues. Due to the unique microenvironment and cell communication in EB structure that a 2D culture system cannot achieve, EBs have been widely applied in hiPSC-derived differentiation and show significant advantages especially in scaling up culturing, differentiation efficiency enhancement, ex vivo simulation, and organoid establishment. EBs can potentially also be used in early prediction of iPSC differentiation capability. To improve the stability and feasibility of EB-mediated differentiation and generate high quality EBs, critical factors including iPSC pluripotency maintenance, generation of uniform morphology using micro-pattern 3D culture systems, proper cellular density inoculation, and EB size control are discussed on the basis of both published data and our own laboratory experiences. Collectively, the production of a large quantity of homogeneous EBs with high quality is important for the stability and feasibility of many PSCs related studies.
ABSTRACT
On account of the biological significance of self-assembling peptides in blocking the cellular mass exchange as well as impeding the formation for actin filaments resulting in program cell death, stimuli-responsive polypeptide nanoparticles have attracted more and more attention. In this work, we successfully fabricated doxorubicin-loaded polyethylene glycol-block-peptide (FFKY)-block-tetraphenylethylene (PEG-Pep-TPE/DOX) nanoparticles, where the aggregation-induced emission luminogens (AIEgen, TPE-CHO) can become a fluorescence resonance energy transfer (FRET) pair with the entrapped antitumor drug DOX to detect the release of drugs dynamically. This is the first successful attempt to detect and quantify the change of FRET signals in A549 cells via three methods to monitor the cellular uptake of nanoprobes and intracellular drug molecule release intuitively. As we proposed here, the combination of free DOX and the self-assembling peptide could achieve the synergistic anticancer efficacy. The multifunctional PEG-Pep-TPE/DOX nanoparticles may provide a new opportunity for combination cancer therapy and real-time detection of the drug release from stimuli-responsive nanomedicine.
Subject(s)
Antineoplastic Agents/chemistry , Doxorubicin/chemistry , Fluorescence Resonance Energy Transfer/methods , Nanoparticles/chemistry , Peptides/chemistry , Polyethylene Glycols/chemistry , Stilbenes/chemistry , A549 Cells , Antineoplastic Agents/metabolism , Antineoplastic Agents/pharmacology , Biocompatible Materials/chemistry , Biocompatible Materials/pharmacology , Cell Survival/drug effects , Doxorubicin/metabolism , Doxorubicin/pharmacology , Drug Carriers/chemistry , Drug Liberation , Glutathione/chemistry , Humans , Hydrogen-Ion Concentration , Luminescent Agents/chemistry , Nanoparticles/toxicityABSTRACT
Self-assembled peptide nanofibers have been widely studied in cancer nanotherapeutics with their excellent biocompatibility and low toxicity of degradation products, showing the significant potential in inhibiting tumor progression. However, poor solubility prevents direct intravenous administration of nanofibers. Although water-soluble peptide precursors have been formed via the method of phosphorylation for intravenous administration, their opportunities for broad in vivo application are limited by the weak capacity of encapsulating drugs. Herein, we designed a novel restructured reduced glutathione (GSH)-responsive drug delivery system encapsulating doxorubicin for systemic administration, which achieved the intracellular restructuration from three-dimensional micelles into one-dimensional nanofibers. After a long blood circulation, micelles endocytosed by tumor cells could degrade in response to high GSH levels, achieving more release and accumulation of doxorubicin at desired sites. Further, the synergistic chemotherapy effects of self-assembled nanofibers were confirmed in both in vitro and in vivo experiments.
Subject(s)
Doxorubicin/administration & dosage , Drug Carriers/pharmacokinetics , Drug Delivery Systems/methods , Glutathione/metabolism , Nanofibers/chemistry , A549 Cells , Animals , Antibiotics, Antineoplastic/administration & dosage , Antibiotics, Antineoplastic/pharmacokinetics , Doxorubicin/pharmacokinetics , Drug Carriers/administration & dosage , Drug Carriers/chemical synthesis , Drug Liberation , Drug Synergism , Endocytosis/drug effects , Glutathione/blood , Human Umbilical Vein Endothelial Cells , Humans , Hydrophobic and Hydrophilic Interactions , Mice, Inbred BALB C , Micelles , Peptides/chemistry , Tissue Distribution , Xenograft Model Antitumor AssaysABSTRACT
Objective: This study was aimed to develop DOX-TPP loaded acetal-PEG-PCCL micelles to improve the clinical efficacy of drug resistance tumor. Significance: Chemotherapy is one of the main treatments for breast cancer but is plagued by multidrug resistance (MDR). DOX-TPP-loaded micelles can enhance the specific concentration of drugs in the tumor and improve the efficacy and overcome MDR. Methods: In this study, DOX-TPP-loaded micelles based on acetal-PEG-PCCL were prepared and their physicochemical properties were characterized. The cellular uptake and ability to induce apoptosis of the micelles was confirmed by flow cytometry in MCF-7/ADR cells. In addition, cytotoxicity of the micelles was studied in MCF-7 cells and MCF-7/ADR cells. Confocal is used to study the subcellular distribution of DOX. Free DOX-TPP or DOX-TPP-loaded acetal-PEG-PCCL micelles were administered via intravenous injection in the tail vain for the biodistribution study in vivo. Results: The diameter of micelles was about 102.4 nm and their drug-loading efficiency is 61.8%. The structural characterization was confirmed by 1H NMR. The micelles exhibited better antitumor efficacy compared to free doxorubicin in MCF-7/ADR cells by MTT assay. The apoptotic rate and the cellular uptake of micelles were significantly higher than free DOX and DOX-TPP. Micelles can efficiently deliver mitochondria-targeting DOX-TPP to tumor cells. The result of bio-distribution showed that the micelles had stronger tumor infiltration ability than free drugs. Conclusions: In this study, mitochondriotropic DOX-TPP was conjugated to the nanocarrier acetal-PEG-PCCL via ionic interaction to form a polymer, which spontaneously formed spherical micelles. The cytotoxicity and cellular uptake of the micelles are superior to free DOX and exhibit mitochondrial targeting and passive tumor targeting, indicating that they have potential prospects.
Subject(s)
Antineoplastic Agents/administration & dosage , Breast Neoplasms/drug therapy , Doxorubicin/administration & dosage , Nanoconjugates/chemistry , Organophosphorus Compounds/administration & dosage , Acetals/chemistry , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacokinetics , Apoptosis/drug effects , Breast Neoplasms/pathology , Doxorubicin/analogs & derivatives , Doxorubicin/pharmacokinetics , Drug Compounding , Drug Resistance, Multiple , Drug Resistance, Neoplasm , Drug Screening Assays, Antitumor , Female , Humans , MCF-7 Cells , Micelles , Mitochondria/drug effects , Mitochondria/pathology , Organophosphorus Compounds/chemistry , Organophosphorus Compounds/pharmacokinetics , Polyesters/chemistry , Polyethylene Glycols/chemistry , Tissue DistributionABSTRACT
Induced pluripotent stem cells (iPSCs) show huge variations in their differentiation potential, even in the same condition. However, methods for predicting these differentiation tendencies, especially in the early stage of differentiation, are still scarce. This study aimed to establish a simple and practical system to predict the differentiation tendency of iPSC lines using embryoid bodies (EBs) with identified parameters in the early stage. We compared four human iPSC lines in terms of the morphology and maintenance of EBs and their gene expression levels of specific markers for three germ-layers. Furthermore, the differentiation potentials of these iPSC lines into melanocytes, which are ectoderm-derived cells, were also compared and correlated with the above parameters. The results showed that iPSC lines forming regular, smooth, and not cystic EBs, which could be maintained in culture for a relatively longer time, also expressed higher levels of ectoderm-specific markers and lower levels of mesoderm/endoderm markers. Additionally, these iPSC lines showed greater potential in melanocyte differentiation using EB-based protocol, and the induced melanocytes expressed melanocytic markers and presented characteristics that were similar to those of normal human melanocytes. By contrast, iPSC lines that formed cystic EBs with bright or dark cavities and expressed relatively lower levels of ectoderm-specific markers failed in the melanocyte differentiation. Collectively, the differentiation tendency of human iPSC lines may be predicted by specific parameters in the EB stage. The formation and maintenance of optimal EBs and the expression of germ layer-specific markers are particularly important and practical for the prediction assay in the early stage.
Subject(s)
Cell Differentiation/genetics , Embryoid Bodies/metabolism , Embryonic Stem Cells/metabolism , Induced Pluripotent Stem Cells/metabolism , Melanocytes/metabolism , Animals , Cell Line , Cells, Cultured , Embryoid Bodies/cytology , Embryonic Stem Cells/cytology , Gene Expression Regulation, Developmental , Germ Layers/cytology , Germ Layers/metabolism , Humans , Induced Pluripotent Stem Cells/cytology , Male , Melanocytes/cytology , Mice, Inbred NOD , Mice, SCID , Nanog Homeobox Protein/genetics , Nanog Homeobox Protein/metabolism , Octamer Transcription Factor-3/genetics , Octamer Transcription Factor-3/metabolism , SOXB1 Transcription Factors/genetics , SOXB1 Transcription Factors/metabolismABSTRACT
Induced pluripotent stem cells (iPSCs) are a promising melanocyte source as they propagate indefinitely and can be established from patients. However, the in vivo functions of human iPSC-derived melanocytes (hiMels) remain unknown. Here, we generated hiMels from vitiligo patients using a three-dimensional system with enhanced differentiation efficiency, which showed characteristics of human epidermal melanocytes with high sequence similarity and involved in multiple vitiligo-associated signaling pathways. A modified hair follicle reconstitution assay in vivo showed that MITF+PAX3+TYRP1+ hiMels were localized in the mouse hair bulb and epidermis and produced melanin up to 7 weeks after transplantation, whereas MITF+PAX3+TYRP1- hiMelanocyte stem cells integrated into the bulge-subbulge regions. Overall, these data demonstrate the long-term functions of hiMels in vivo to reconstitute pigmented hair follicles and to integrate into normal regions for both mature melanocytes and melanocyte stem cells, providing an alternative source of personalized cellular therapy for depigmentation.
Subject(s)
Induced Pluripotent Stem Cells/metabolism , Induced Pluripotent Stem Cells/transplantation , Melanocytes/metabolism , Stem Cell Transplantation/methods , Animals , Humans , Mice , Rabbits , Transplantation, AutologousABSTRACT
As an important disulfide reductase of the intracellular antioxidant system, Thioredoxin (Trx) plays an important role in maintaining oxidative stress balance and protecting cells from oxidative damage. In recent years, there is increasing evidence that Trx is a key molecule in the pathogenesis of various diseases and a potential therapeutic target for major diseases including lung, colon, cervical, gastric and pancreatic cancer. However, few knowledge is known about the function of Trx in virus infection. In this study, we reported the cloning and functional investigation of a Trx homologue gene, named MjTrx, in shrimp Marsupenaeus japonicus suffered white spot syndrome virus (WSSV) infection. MjTrx is a 105-amino acid polypeptide with a conservative Cys-Gly-Pro-Cys motif in the catalytic center. Phylogenetic trees analysis showed that MjTrx has a higher relationship with Trx from other invertebrate and clustered with Trx1 from arthropod. MjTrx transcripts is abundant in the gill and intestine tissues and can be detected in the hemocytes, heart, stomach, and hepatopancreas tissues. The transcription levels of MjTrx in hemocytes, gills and intestine tissues of shrimp were significantly up-regulated after white spot syndrome virus infection. MjTrx was recombinant expressed in vitro and exhibited obvious disulfide reductase activity. In addition, overexpression MjTrx in shrimp resulted in the increase of hydrogen peroxide (H2O2) concentration in vivo. All these results strongly suggested that MjTrx functioned in redox homeostasis regulating and played an important role in shrimp antiviral immunity.
Subject(s)
Gene Expression Regulation/immunology , Immunity, Innate/genetics , Penaeidae/genetics , Penaeidae/immunology , Thioredoxins/genetics , Thioredoxins/immunology , Amino Acid Sequence , Animals , Arthropod Proteins/chemistry , Arthropod Proteins/genetics , Arthropod Proteins/immunology , Base Sequence , Gene Expression Profiling , Phylogeny , Sequence Alignment , Thioredoxins/chemistry , White spot syndrome virus 1/physiologyABSTRACT
Breast cancer is the leading cause of cancer-related death for women, and multidrug resistance (MDR) is the major obstacle faced by chemotherapy for breast cancer. We have previously synthesized a doxorubicin (DOX) derivative by conjugating DOX with triphenylphosphonium (TPP) to achieve mitochondrial delivery, which induced higher cytotoxicity in drug-resistant breast cancer cells than DOX itself. Due to its amphiphilicity, TPP-DOX is difficult to physically entrap in nanocarriers. Thus, we linked it to hyaluronic acid (HA) by a novel ionic bond utilizing the specific bromide ion of TPP to form supra-molecular self-assembled structures (HA-ionic-TPP-DOX). The product was analyzed uisng 1H-NMR, 13C-NMR and mass spectrometry. The HA nanocarriers (HA-ionic-TPP-DOX) were shown to self-assemble into spherical nanoparticles, and sensitive to acidic pH in terms of morphology and drug release. Compared with free DOX, HA-ionic-TPP-DOX produced much greater intracellular DOX accumulation and mitochondrial localization, leading to increased ROS production, slightly decreased mitochondrial membrane potential, increased cytotoxicity in MCF-7/ADR cells and enhanced tumor targeting in vivo. In xenotransplant zebrafish model with the MCF-7/ADR cell line, both TPP-DOX and HA-ionic-TPP-DOX inhibited tumor cell proliferation without inducing significant side effects compared with free DOX. In addition, we observed a better anti-tumor effect of HA-ionic-TPP-DOX on MCF-7/ADR cells in zebrafish than that of TPP-DOX treatment. Furthermore, HA-ionic-DOX-TPP exhibited favorable biocompatibility and anti-tumor effects in MCF-7/ADR tumor-bearing nude mice in comparison with the effects of TPP-DOX and DOX, suggesting the potential of HA-ionic-TPP-DOX for the targeted delivery and controlled release of TPP-DOX, which can lead to the sensitization of resistant breast tumors.
Subject(s)
Antineoplastic Agents/therapeutic use , Breast Neoplasms/drug therapy , Doxorubicin/therapeutic use , Drug Carriers/chemistry , Hyaluronic Acid/chemistry , Mitochondria/metabolism , Animals , Antineoplastic Agents/chemistry , Apoptosis/drug effects , Doxorubicin/chemistry , Drug Liberation , Drug Resistance, Neoplasm/drug effects , Female , Humans , MCF-7 Cells , Membrane Potential, Mitochondrial/drug effects , Mice, Inbred BALB C , Mice, Nude , Onium Compounds/chemistry , Organophosphorus Compounds/chemistry , ZebrafishABSTRACT
Multidrug resistance (MDR) is the major obstacle for chemotherapy. In a previous study, we have successfully synthesized a novel doxorubicin (DOX) derivative modified by triphenylphosphonium (TPP) to realize mitochondrial delivery of DOX and showed the potential of this compound to overcome DOX resistance in MDA-MB-435/DOX cells. (1) To introduce specificity for DOX-TPP to cancer cells, here we report on the conjugation of DOX-TPP to hyaluronic acid (HA) by hydrazone bond with adipic acid dihydrazide (ADH) as the acid-responsive linker, producing HA- hydra-DOX-TPP nanoparticles. Hyaluronic acid (HA) is a natural water-soluble linear glycosaminoglycan, which was hypothesized to increase the accumulation of nanoparticles containing DOX-TPP in the mitochondria of tumor cells upon systemic administration, overcoming DOX resistance, in vivo. Our results showed HA- hydra-DOX-TPP to self-assemble to core/shell nanoparticles of good dispersibility and effective release of DOX-TPP from the HA- hydra-DOX-TPP conjugate in cancer cells, which was followed by enhanced DOX mitochondria accumulation. The HA- hydra-DOX-TPP nanoparticles also showed improved anticancer effects, better tumor cell apoptosis, and better safety profile compared to free DOX in MCF-7/ADR bearing mice.
Subject(s)
Antibiotics, Antineoplastic/administration & dosage , Breast Neoplasms/drug therapy , Doxorubicin/administration & dosage , Mitochondria/metabolism , Nanoconjugates/chemistry , Animals , Antibiotics, Antineoplastic/chemistry , Apoptosis/drug effects , Breast Neoplasms/pathology , Doxorubicin/chemistry , Drug Liberation , Drug Resistance, Multiple , Drug Resistance, Neoplasm , Female , Humans , Hyaluronan Receptors/metabolism , Hyaluronic Acid/chemistry , Hydrogen-Ion Concentration , Lysosomes/drug effects , Lysosomes/metabolism , MCF-7 Cells , Mice , Mice, Inbred BALB C , Mice, Nude , Mitochondria/drug effects , Organophosphorus Compounds/administration & dosage , Organophosphorus Compounds/chemistry , Tissue Distribution , Xenograft Model Antitumor AssaysABSTRACT
Currently, the limited penetration of nanoparticles remains a major challenge for antitumor nanomedicine to penetrate into the tumor tissues. Herein, we propose a size-shrinkable drug delivery system based on a polysaccharide-modified dendrimer with tumor microenvironment responsiveness for the first time to our knowledge, which was formed by conjugating the terminal glucose of hyaluronic acid (HA) to the superficial amidogen of poly(amidoamine) (PAMAM), using a matrix metalloproteinase-2 (MMP-2)-cleavable peptide (PLGLAG) via click reaction. These nanoparticles had an initial size of â¼200 nm, but once deposited in the presence of MMP-2, they experienced a dramatic and fast size change and dissociated into their dendrimer building blocks (â¼10 nm in diameter) because of cleavage of PLGLAG. This rapid size-shrinking characteristic not only promoted nanoparticle extravasation and accumulation in tumors benefited from the enhanced permeability and retention effect but also achieved faster nanoparticle diffusion and penetration. We have further conducted comparative studies of MMP-2-sensitive macromolecules (HA-pep-PAMAM) and MMP-2-insensitive macromolecules (HA-PAMAM) synthesized with a similar particle size, surface charge, and chemical composition and evaluated in both monolayer cells and multicellular spheroids. The results confirmed that the enzyme-responsive size shrink is an implementable strategy to enhance drug penetration and to improve therapeutic efficacy. Meanwhile, macromolecule-based nanoparticles with size-variable characteristics not only promote drug penetration, but they can also be used as gene delivery systems, suggesting great potential as nano-delivery systems.
Subject(s)
Dendrimers/chemistry , Cell Line, Tumor , Drug Delivery Systems , Humans , Hyaluronic Acid , Matrix Metalloproteinase 2 , PolyaminesABSTRACT
PURPOSE: [(11)C]NNC 112 and [(11)C]SCH 23390 are selective positron emission tomography (PET) tracers for visualizing dopamine D(1) receptors. It is known that both have some affinity for serotonin 2A receptors, but previous studies have suggested this is negligible compared to D(1) affinity. We sought to verify this property in vivo. PROCEDURES: Two baboons were scanned to measure the selectivity of both tracers with a displacement paradigm. Four baboons were scanned to directly assess [(11)C] NNC 112 affinity for both receptors. RESULTS: In vivo, D(1) to 5-HT(2A) selectivity is six to fourteenfold, not 100-fold as previously reported by other investigators. CONCLUSION: We conclude that about 1/4 of the cortical signal of both [(11)C]NNC 112 and [(11)C]SCH 23390 is due to binding to 5-HT(2A) receptors. If confirmed in humans, this suggests caution should be exercised when drawing conclusions from studies using either tracer. These results also indicate the need for more selective tracers for the D(1) receptor.